// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_MOJO_CLIENTS_MOJO_VIDEO_DECODER_H_
#define MEDIA_MOJO_CLIENTS_MOJO_VIDEO_DECODER_H_

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "media/base/video_decoder.h"
#include "media/mojo/interfaces/video_decoder.mojom.h"
#include "mojo/public/cpp/bindings/associated_binding.h"

namespace base {
class SingleThreadTaskRunner;
}

namespace media {

class GpuVideoAcceleratorFactories;
class MojoDecoderBufferWriter;

// A VideoDecoder, for use in the renderer process, that proxies to a
// mojom::VideoDecoder. It is assumed that the other side will be implemented by
// MojoVideoDecoderService, running in the GPU process, and that the remote
// decoder will be hardware accelerated.
class MojoVideoDecoder final : public VideoDecoder,
                               public mojom::VideoDecoderClient {
public:
    MojoVideoDecoder(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
        GpuVideoAcceleratorFactories* gpu_factories,
        mojom::VideoDecoderPtr remote_decoder);
    ~MojoVideoDecoder() final;

    // VideoDecoder implementation.
    std::string GetDisplayName() const final;
    void Initialize(const VideoDecoderConfig& config,
        bool low_delay,
        CdmContext* cdm_context,
        const InitCB& init_cb,
        const OutputCB& output_cb) final;
    void Decode(const scoped_refptr<DecoderBuffer>& buffer,
        const DecodeCB& decode_cb) final;
    void Reset(const base::Closure& closure) final;
    bool NeedsBitstreamConversion() const final;
    bool CanReadWithoutStalling() const final;
    int GetMaxDecodeRequests() const final;

    // mojom::VideoDecoderClient implementation.
    void OnVideoFrameDecoded(mojom::VideoFramePtr frame) final;

private:
    void OnInitializeDone(bool status,
        bool needs_bitstream_conversion,
        int32_t max_decode_requests);
    void OnDecodeDone(uint64_t decode_id, DecodeStatus status);
    void OnResetDone();

    void BindRemoteDecoder();

    // Cleans up callbacks and blocks future calls.
    void Stop();

    // Task runner that the decoder runs on (media thread).
    scoped_refptr<base::SingleThreadTaskRunner> task_runner_;

    // Used to pass the remote decoder from the constructor (on the main thread)
    // to Initialize() (on the media thread).
    mojom::VideoDecoderPtrInfo remote_decoder_info_;

    GpuVideoAcceleratorFactories* gpu_factories_ = nullptr;

    InitCB init_cb_;
    OutputCB output_cb_;
    uint64_t decode_counter_ = 0;
    std::map<uint64_t, DecodeCB> pending_decodes_;
    base::Closure reset_cb_;

    mojom::VideoDecoderPtr remote_decoder_;
    std::unique_ptr<MojoDecoderBufferWriter> mojo_decoder_buffer_writer_;
    bool remote_decoder_bound_ = false;
    bool has_connection_error_ = false;
    mojo::AssociatedBinding<VideoDecoderClient> client_binding_;

    bool initialized_ = false;
    bool needs_bitstream_conversion_ = false;
    int32_t max_decode_requests_ = 1;

    DISALLOW_COPY_AND_ASSIGN(MojoVideoDecoder);
};

} // namespace media

#endif // MEDIA_MOJO_CLIENTS_MOJO_VIDEO_DECODER_H_
